It is desirable to have a weapon that can destroy a variety of targets. For example, targets such as command and control centers are often buried underground and hardened with reinforced concrete overburdens. Heavily armored targets such as heavy tanks may be protected by multiple layers of hard armor, the defeat of which requires substantial penetration capability focused on a single impact point on the target. The defeat of other targets such as light armored vehicles and unarmored trucks can be enhanced by multiple impacts in different locations on the target.
One type of weapon that can be used to penetrate and destroy these kinds of targets is a projectile which impacts and penetrates a target by virtue of its kinetic energy, rather than by explosive energy. However, when such a projectile consists of only a single penetrator element, substantial stresses may be applied to the projectile by initial contact with the target or by certain features of the armor protection, and the impact may result in the breakup of the projectile with very little damage to the target. In addition, when a penetrator is employed at hyper velocity, a single large impacting element is not as effective in penetration of heavy armor as the same mass divided into a plurality of impact segments that each impact the target in the same location.
Thus, improved penetration can be achieved by a projectile having multiple penetrator segments that sequentially impact the target. One such penetrator has multiple non-aerodynamically stable segments, each having a nose portion and a rearwardly opening cavity. The segments are stacked such that the nose portion of a segment is positioned in the cavity of an immediately preceding segment. The segments are separated during flight by initiation of a time-to-go fuze. U.S. Pat. No. 5,088,416 discloses a projectile having multiple impact bodies positioned sequentially along a central rod which holds the impact bodies in initial axial alignment. After a predetermined flight time, the impact bodies are released and biased apart by springs or dished washers so that the impact bodies spread apart along the rod. The impact bodies then successively impact the target so that each impact body independently attacks the target with its full kinetic energy.
Similarly, U.S. Pat. No. 4,716,834 discloses a projectile having a pre-penetrator and a main penetrator. The pre-penetrator contains a plurality of stacked cylindrical cores in axial alignment with each other. Centering and/or fixing means between the cores include a weakened portion so as to achieve a fracturing or separation upon the application of a predetermined load. When the projectile impacts a target, the leading core in the stack impacts the target and disintegrates, followed by the impact of the next core in the stack, and so on until all the cores have successively impacted the target. U.S. Pat. No. 4,708,064 discloses a similar projectile having a plurality of stacked cores contained within the projectile. The cores are intermitted and connected together by centering and/or fixing means which break upon impact, such as a thin-walled and comparatively soft casing or easily rupturable pins, which hold the cores in alignment until impact. When the projectile impacts a target, each core sequentially impacts the target in the same location while the centering and/or fixing means tear away from the impact so as not to adversely interfere with the impact of each core. U.S. Pat. No. 4,635,556 discloses a penetrator that has a stack of interfitted core elements having partially convex front faces and complementary partially concave rear faces, and which are contained within a casing. A main penetrator body interfits with the rearmost core element and a tip at the front of the forwardmost core elements presses the core elements toward the main penetrator body. The core elements form radially outwardly open annular grooves at the faces which allow the penetrator to break apart at these grooves. Upon reaching the target, each core element sequentially impacts the target.
Other kinds of multistage penetrators include the projectile disclosed by U.S. Pat. No. 5,526,752, which contains multiple warheads mounted in tandem within the casing of the projectile. Upon reaching a target, a fuzing mechanism located at the front of the casing causes the warheads to detonate sequentially, starting with the rearmost warhead to the frontmost warhead. U.S. Pat. No. 4,901,645 discloses a projectile having a single penetrator rod that has a plurality of annular grooves. Upon impact, the rod breaks along the grooves, allowing the rod to separate into sections that then separately impact the target in the same location.
One disadvantage of the above described penetrators is that the effectiveness and location of the impact of each impact body, core, warhead or rod section (all referred to as penetrator segments) depends on the impact of the preceding penetrator segment. Because the segments of these penetrators are held closely together up to the point of impact, either by a central rod or by containment within the penetrator, each segment will impact the same location on the target almost immediately after the impact of the preceding segment. If the preceding segment does not fully disintegrate immediately upon impact, then the impact of the next segment will be disrupted by the debris and remnants from the preceding impact. A greater distance between the segments, thereby allowing for a greater amount of time between impacts, would allow each segment to impact the target after the preceding segment has fully disintegrated and the gases and/or remnants of the preceding impact have been exhausted. The above described penetrators do not allow for a significant distance between the segments due to size constraints of the projectile, both for storage and deployment purposes.
Furthermore, because each of the segments in these penetrators is held in axial alignment until impact, these penetrators are constrained to impacting a target at a single location. While sequential impact in a single location can be desirable for penetrating buried and/or multilayered targets, other targets may be more suitably defeated by multiple impacts in several locations. The above described projectiles cannot impact a target at multiple locations, even though the penetrators contain multiple impact segments.
The inventor of the invention claimed herein has previously filed a U.S. patent application, Ser. No. 08/699,225, entitled "Penetrator Having Multiple Impact Segments" now U.S. Pat No. 5,384,684, that is suitable for solving the above listed problems. Application Ser. No. 08/699,225 discloses a penetrator comprised of a plurality of stacked penetrator segments, including a leading penetrator segment, at least one intermediate penetrator segment, and a trailing penetrator segment, all sequentially positioned along the longitudinal axis of the penetrator. Each penetrator segment has a nose portion and a rear portion. The rear portion of the leading penetrator segment and of each intermediate penetrator segment has a plurality of fins pivotally mounted thereon and a rearwardly opening cavity. The rear portion of the trailing penetrator segment has an enlarged tail. The penetrator segments are stacked along the longitudinal axis of the penetrator such that the rearwardly opening cavity of the leading penetrator segment contains the nose portion of the forwardmost intermediate penetrator segment. Each intermediate penetrator segment is stacked with its nose portion positioned within the rearwardly opening cavity of the immediately preceding penetrator segment. The penetrator segments are further stacked such that the nose portion of the trailing penetrator segment is positioned within the rearwardly opening cavity of the rearmost intermediate penetrator segment.
Each fin on the penetrator segments has a stabilizing portion and a deployment preventing arm. The deployment preventing arm contacts the nose portion of the immediately following penetrator segment when that nose portion is fully inserted into the respective rearwardly opening cavity. The contact between the nose portion and the deployment preventing arm of each fin prevents the fins from pivoting to their deployed positions and causes the fins to be restrained in their stowed positions. When the nose portion withdraws from the rearwardly opening cavity, the contact between the nose portion and the arm of each fin is discontinued, thereby permitting the fins of the penetrator segment to pivot to their deployed positions.
Upon launching the penetrator, aerodynamic drag against the enlarged tail of the trailing penetrator segment causes the velocity of the trailing penetrator segment to decrease with respect to the remaining stacked penetrator segments. The nose portion of the trailing penetrator segment thereby withdraws from the rearwardly opening cavity of the rearmost intermediate penetrator segment and the trailing penetrator segment thus separates from the remaining stacked penetrator segments. The withdrawal of the nose portion of the trailing penetrator segment from the rearwardly opening cavity of the rearmost intermediate penetrator segment permits the fins of the rearmost positioned intermediate penetrator segment to deploy. The stabilizing portions of the deployed fins of the rearmost intermediate penetrator segment encounter aerodynamic drag, thus decreasing the velocity of the rearmost intermediate penetrator segment. The nose portion of the rearmost intermediate penetrator segment thereby withdraws from the rearwardly opening cavity of the immediately preceding penetrator segment, which thus permits the fins of the immediately preceding penetrator segment to deploy. The fins of each of the at least one intermediate penetrator segment are similarly allowed to deploy, until the forwardmost intermediate penetrator segment separates from the leading penetrator segment. Thereupon, the penetrator has fully separated into discrete penetrator segments which are aerodynamically stabilized and which can sequentially impact a target. By initiating separation of the penetrator segments at an appropriately short distance from the target, the separated penetrator segments can then impact the target in a collinear manner so that each penetrator segment impacts the target in the same location. Alternatively, by initiating separation of the penetrator segments at a sufficiently long distance from the target, the penetrator segments will disperse due to aerodynamic asymmetries, thereby causing the penetrator segments to impact the target in multiple locations.
This penetrator can be improved upon by increasing the stability of the penetrator in its undeployed state. The preferred embodiment of the penetrator described in application serial number 08/699,225 shows segments having conical shaped noses that fit within conical shaped cavities of the rear portions of the segments. The conical shape of the noses and cavities allows for only limited stability of the overall penetrator in its undeployed configuration. The stability can be enhanced by the use of a central connecting rod or wire running along the longitudinal axis of the segments, but the rod or wire, can interfere with the penetrator both during flight and upon impact. If the center rod or wire is eliminated, the segments will begin to separate immediately upon deployment of the penetrator, which does not allow for controlled timing of the separation of the segments. Moreover, because upon deployment, the segments aerodynamically separate from the rearmost segment forward, the rearmost segment may be excessively spaced apart from the preceding penetrator segments by the time the forwardmost penetrator segment is suitably spaced from the following penetrator segments. It is therefore desirable to control the spacing between the segments and the axial alignment of the segments to maximize the destructive capability of the penetrator. It is also desirable to have a multiple-segment penetrator that has enhanced stability in its undeployed configuration and which can separate during deployment such that the segment spacing can be controlled prior to impact with the target.